901 series
The 901 series, later the 209-900, 209-910 and 209-920 series, is a group of three Japanese ten-car commuter electric multiple units. Built from 1992 for JR East, the 901 series acted as the prototype of the then-soon-to-be-produced 209 series, and was used on services on the Keihin-Tōhoku and Negishi Lines until all three were retired in 2007. History The 901 series was designed in 1992 as a prototype "new-generation train" for use by the then-newly formed JR East. Three ten-car sets were built in 1992; sets A, B and C. Set A was built by Kawasaki Heavy Industries, Set B was built by Tokyu Car Corporation and Set C was jointly built by Kawasaki Heavy Industries and JR East's Ōfuna Works. All 3 sets entered service on 7 May 1992, with sets A and C carrying a special headboard to commemorate the event. The sets were refurbished in 1994 to make them more in-line with the mass-production 209 series sets for which they served as the prototype for, and were reclassified; set A was reclassified as the 209-900 series set Ura90, set B as 209-910 series set Ura91 and set C as 209-920 series set Ura92. All three sets were based at Urawa Depot (now Saitama Depot). The sets were slowly retired from 2006; set Ura90 retired on 28 August 2007, set Ura91 retired on 19 December 2006 and set Ura92 retired on 7 March 2007. All cars met their final fate at the scrapper's torch, except car KuHa 209 901 from set Ura90; the car was stored at Nagano Depot for a time, but was later moved to the Tokyo General Rolling Stock Center to be put on display, where it remains today. Design The 901 series uses a modern design with an unpainted stainless steel body very much like most JR East commuter trains; their appearance is identical to the 209-0 series sets that would soon follow. Specifications Construction is of stainless steel. Cars are 20 meters long and 2.87 meters wide. All 901 series sets were different in some way or another, including the variable frequency drives used. Set A used a very strange power transistor-based system made by Fuji Electric that made a quiet hiss when accelerating from idle; the system was later changed to a gate turn-off thyristor variable frequency drive made by Mitsubishi in 2001 as the power transistor system was unable to respond to the digital ATC signal produced on the Keihin-Tōhoku Line. This same GTO system was adopted by the full-production sets. Set B used a more generic GTO-VVVF system manufactured by Toshiba, while set C used a three-level GTO-VVVF system made by Mitsubishi; the Mitsubishi system was adopted by the full-production 209 series sets. Other than the above differences, each set has its own unique differences when it comes to bodywork. Set A had big one-piece side windows, pneumatically-operated passenger doors and screw-type air compressors, set B had two-piece side windows, electrically-operated passenger doors and reciprocating-type air compressors and set C had two-piece side windows, pneumatically-operated passenger doors and reciprocating-type air compressors along with ductless air conditioners. References *Wikipedia.org Category:Electric Trainsets Category:JR Group trains